Anyone in the Kent (UK) area is welcome to join :)
Have you joined the UK group on here? http://realpagan.net/group/pagansintheuk
Post this on there, you may get some local intrest there.
Also you may want to try Witchvox.com too. They list lots of local groups, so you can post there, or find a group to join.
I got involved with my first coven via a moot in a pub which I heard of through the local "pagan" book shop (in the days before the internet). A moot is a great way to meet people, an informal setting to chat before you decide to go to someones house/invite them to yours.